Had some trouble with charging an M18 battery Saturday night. Most likely user-error. I keep my charger (normal, dual-type M18 & M12) in the (uninsulated) garage, right near the main doors.
Outside temp was in the low teens °F (or less). Inside the garage couldn't have been much warmer.
Was trying to change an M18 battery that I'd just used with my inflator to top off a tire. That had been stored in my truck. Battery was down to one bar, but worked perfectly.
Plugged the battery into the charger, got a blinking red light. Unplugged the charger, pushed the battery button again (while still in the charger), got the alternating green and red blinking lights on the charger.
Brought the battery and charger into the house, let them warm up overnight, everything is fine now.
I really don't "want" to have to have the charger and batteries indoors all the time, but is that the proper way to charge them?
BTW, the charger is from my initial M18 purchase in 2020. Not sure about the battery, could be that old, or newer, as I've been slowly expanding the herd of M18 tools and batteries over the years.
Mike